1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2007 PA Semi, Inc
5 * Authors: Egor Martovetsky <egor@pasemi.com>
6 * Olof Johansson <olof@lixom.net>
8 * Maintained by: Olof Johansson <olof@lixom.net>
10 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
11 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
14 #include <linux/cpufreq.h>
15 #include <linux/timer.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
19 #include <asm/hw_irq.h>
25 #define SDCASR_REG 0x0100
26 #define SDCASR_REG_STRIDE 0x1000
27 #define SDCPWR_CFGA0_REG 0x0100
28 #define SDCPWR_PWST0_REG 0x0000
29 #define SDCPWR_GIZTIME_REG 0x0440
31 /* SDCPWR_GIZTIME_REG fields */
32 #define SDCPWR_GIZTIME_GR 0x80000000
33 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
35 /* Offset of ASR registers from SDC base */
36 #define SDCASR_OFFSET 0x120000
38 static void __iomem *sdcpwr_mapbase;
39 static void __iomem *sdcasr_mapbase;
41 /* Current astate, is used when waking up from power savings on
42 * one core, in case the other core has switched states during
45 static int current_astate;
47 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
48 static struct cpufreq_frequency_table pas_freqs[] = {
54 {0, 0, CPUFREQ_TABLE_END},
58 * hardware specific functions
61 static int get_astate_freq(int astate)
64 ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
69 static int get_cur_astate(int cpu)
73 ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
74 ret = (ret >> (cpu * 4)) & 0x7;
79 static int get_gizmo_latency(void)
83 giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
85 /* just provide the upper bound */
86 if (giztime & SDCPWR_GIZTIME_GR)
87 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
89 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
94 static void set_astate(int cpu, unsigned int astate)
98 /* Return if called before init has run */
99 if (unlikely(!sdcasr_mapbase))
102 local_irq_save(flags);
104 out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
106 local_irq_restore(flags);
109 int check_astate(void)
111 return get_cur_astate(hard_smp_processor_id());
114 void restore_astate(int cpu)
116 set_astate(cpu, current_astate);
123 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
125 struct cpufreq_frequency_table *pos;
126 const u32 *max_freqp;
130 struct device_node *cpu, *dn;
133 cpu = of_get_cpu_node(policy->cpu, NULL);
137 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
144 /* we need the freq in kHz */
145 max_freq = *max_freqp / 1000;
147 dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
149 dn = of_find_compatible_node(NULL, NULL,
150 "pasemi,pwrficient-sdc");
153 err = of_address_to_resource(dn, 0, &res);
157 sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
158 if (!sdcasr_mapbase) {
163 dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
165 dn = of_find_compatible_node(NULL, NULL,
166 "pasemi,pwrficient-gizmo");
169 goto out_unmap_sdcasr;
171 err = of_address_to_resource(dn, 0, &res);
174 goto out_unmap_sdcasr;
175 sdcpwr_mapbase = ioremap(res.start, 0x1000);
176 if (!sdcpwr_mapbase) {
178 goto out_unmap_sdcasr;
181 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
182 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
183 pr_debug("initializing frequency table\n");
185 /* initialize frequency table */
186 cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
187 pos->frequency = get_astate_freq(pos->driver_data) * 100000;
188 pr_debug("%d: %d\n", idx, pos->frequency);
191 cur_astate = get_cur_astate(policy->cpu);
192 pr_debug("current astate is at %d\n",cur_astate);
194 policy->cur = pas_freqs[cur_astate].frequency;
195 ppc_proc_freq = policy->cur * 1000ul;
197 cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
201 iounmap(sdcasr_mapbase);
206 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
209 * We don't support CPU hotplug. Don't unmap after the system
210 * has already made it to a running state.
212 if (system_state >= SYSTEM_RUNNING)
216 iounmap(sdcasr_mapbase);
218 iounmap(sdcpwr_mapbase);
223 static int pas_cpufreq_target(struct cpufreq_policy *policy,
224 unsigned int pas_astate_new)
228 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
230 pas_freqs[pas_astate_new].frequency,
231 pas_freqs[pas_astate_new].driver_data);
233 current_astate = pas_astate_new;
235 for_each_online_cpu(i)
236 set_astate(i, pas_astate_new);
238 ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
242 static struct cpufreq_driver pas_cpufreq_driver = {
243 .name = "pas-cpufreq",
244 .flags = CPUFREQ_CONST_LOOPS,
245 .init = pas_cpufreq_cpu_init,
246 .exit = pas_cpufreq_cpu_exit,
247 .verify = cpufreq_generic_frequency_table_verify,
248 .target_index = pas_cpufreq_target,
249 .attr = cpufreq_generic_attr,
253 * module init and destoy
256 static int __init pas_cpufreq_init(void)
258 if (!of_machine_is_compatible("PA6T-1682M") &&
259 !of_machine_is_compatible("pasemi,pwrficient"))
262 return cpufreq_register_driver(&pas_cpufreq_driver);
265 static void __exit pas_cpufreq_exit(void)
267 cpufreq_unregister_driver(&pas_cpufreq_driver);
270 module_init(pas_cpufreq_init);
271 module_exit(pas_cpufreq_exit);
273 MODULE_LICENSE("GPL");
274 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");